RedirectToAction help: or better suggestion

Question

Still getting my feet wet with asp.net mvc. I have a working Action and httppost action but I want to replace the "iffy" code with a RedirectToAction call because the code is rather large for what it does. A call using RedirectToAction would clean it up more. Every way I've tried it fails to work for me in that the drop down list fails to have the proper item selected. The code below works fine but calling RedirectToAction the way I have been does not work for me. So how can i rework the code below to use RedirectToAction ?

I find this line of code particularly troubling because there is no garentee that the "this.Url.RequestContext.RouteData.Route" property will be of type "System.Web.Routing.Route".

  // get url request
            var urlValue = "/" + ((System.Web.Routing.Route)(this.Url.RequestContext.RouteData.Route)).Url;

I also find the second piece of code rather bloated ...

  // build the url template
            urlValue = urlValue.Replace("{realm}", realm);
            urlValue = urlValue.Replace("{guild}", guild);
            urlValue = urlValue.Replace("{date}", date.ToShortDateString().Replace("/", "-"));
            urlValue = urlValue.Replace("{pageIndex}", pageIndex.ToString());
            urlValue = urlValue.Replace("{itemCount}", itemCountToDisplay.ToString());

The route I have setup is

  routes.MapRoute(
             "GuildOverview Realm", // Route name
             "GuildMembers/{realm}/{guild}/{date}/{pageIndex}/{itemCount}", // URL with parameters
             new { controller = "GuildMembers", action = "Index" }); // Parameter defaults

The code for my controller actions is below ...

    [HttpPost]
    public ActionResult Index(string realm, string guild, DateTime date, int pageIndex, int itemCount, FormCollection formCollection)
    {
        // get form data if it's there and  try parse num items to display
        var cnt = this.Request.Form["ddlDisplayCount"];
        int itemCountToDisplay = 10;
        if (!string.IsNullOrEmpty(cnt)) int.TryParse(cnt, out itemCountToDisplay);

        // get url request
        var urlValue = "/" + ((System.Web.Routing.Route)(this.Url.RequestContext.RouteData.Route)).Url;

        // build the url template
        urlValue = urlValue.Replace("{realm}", realm);
        urlValue = urlValue.Replace("{guild}", guild);
        urlValue = urlValue.Replace("{date}", date.ToShortDateString().Replace("/", "-"));
        urlValue = urlValue.Replace("{pageIndex}", pageIndex.ToString());
        urlValue = urlValue.Replace("{itemCount}", itemCountToDisplay.ToString());

        return this.Redirect(urlValue);
    }

    public ActionResult Index(string realm, string guild, DateTime date, int pageIndex, int itemCount)
    {
        // get the page index 
        ViewData["pageIndex"] = pageIndex;

        // validate item count 
        var pageItemCountItems = new[] { 10, 20, 50, 100 };
        if (!pageItemCountItems.Contains(itemCount)) itemCount = pageItemCountItems[0];

        //  calc the number of pages there are
        var numPages = (this._repository.GetGuildMemberCount(date, realm, guild) / itemCount) + 1;
        this.ViewData["pageCount"] = numPages;

        // get url request
        var urlValue = "/" + ((System.Web.Routing.Route)(this.Url.RequestContext.RouteData.Route)).Url;

        // build the url template
        urlValue = urlValue.Replace("{realm}", realm);
        urlValue = urlValue.Replace("{guild}", guild);
        urlValue = urlValue.Replace("{date}", date.ToShortDateString().Replace("/", "-"));
        urlValue = urlValue.Replace("{pageIndex}", "{0}");
        urlValue = urlValue.Replace("{itemCount}", itemCount.ToString());

        // set url template
        ViewData["UrlTemplate"] = urlValue;

        //  set list of items for the display count dropdown
        var itemCounts = new SelectList(pageItemCountItems, itemCount);
        ViewData["DisplayCount"] = itemCounts;

        return View(_repository.GetGuildCharacters(date, realm, guild, (pageIndex - 1) * itemCount, itemCount));
    }

and my Index view contains the fallowing

            <%=Html.SimplePager(int.Parse(ViewData["pageIndex"].ToString()),
                                   int.Parse(ViewData["pageCount"].ToString()),
                                   ViewData["urlTemplate"].ToString(),
                                   "nav-menu")%>
            <% using (Html.BeginForm())
               { %>
            <%= Html.DropDownList("ddlDisplayCount", (SelectList)ViewData["DisplayCount"], new { onchange = "this.form.submit();" })%>
            <% }%>